arch/arm/plat-samsung/irq-uart.c

   1 /* arch/arm/plat-samsung/irq-uart.c
   2  *      originally part of arch/arm/plat-s3c64xx/irq.c
   3  *
   4  * Copyright 2008 Openmoko, Inc.
   5  * Copyright 2008 Simtec Electronics
   6  *      Ben Dooks <ben@simtec.co.uk>
   7  *      http://armlinux.simtec.co.uk/
   8  *
   9  * Samsung- UART Interrupt handling
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 as
  13  * published by the Free Software Foundation.
  14  */
  15
  16 #include <linux/kernel.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/serial_core.h>
  19 #include <linux/irq.h>
  20 #include <linux/io.h>
  21
  22 #include <mach/map.h>
  23 #include <plat/irq-uart.h>
  24 #include <plat/regs-serial.h>
  25 #include <plat/cpu.h>
  26
  27 /* Note, we make use of the fact that the parent IRQs, IRQ_UART[0..3]
  28  * are consecutive when looking up the interrupt in the demux routines.
  29  */
  30
  31 static inline void __iomem *s3c_irq_uart_base(unsigned int irq)
  32 {
  33         struct s3c_uart_irq *uirq = get_irq_chip_data(irq);
  34         return uirq->regs;
  35 }
  36
  37 static inline unsigned int s3c_irq_uart_bit(unsigned int irq)
  38 {
  39         return irq & 3;
  40 }
  41
  42 static void s3c_irq_uart_mask(unsigned int irq)
  43 {
  44         void __iomem *regs = s3c_irq_uart_base(irq);
  45         unsigned int bit = s3c_irq_uart_bit(irq);
  46         u32 reg;
  47
  48         reg = __raw_readl(regs + S3C64XX_UINTM);
  49         reg |= (1 << bit);
  50         __raw_writel(reg, regs + S3C64XX_UINTM);
  51 }
  52
  53 static void s3c_irq_uart_maskack(unsigned int irq)
  54 {
  55         void __iomem *regs = s3c_irq_uart_base(irq);
  56         unsigned int bit = s3c_irq_uart_bit(irq);
  57         u32 reg;
  58
  59         reg = __raw_readl(regs + S3C64XX_UINTM);
  60         reg |= (1 << bit);
  61         __raw_writel(reg, regs + S3C64XX_UINTM);
  62         __raw_writel(1 << bit, regs + S3C64XX_UINTP);
  63 }
  64
  65 static void s3c_irq_uart_unmask(unsigned int irq)
  66 {
  67         void __iomem *regs = s3c_irq_uart_base(irq);
  68         unsigned int bit = s3c_irq_uart_bit(irq);
  69         u32 reg;
  70
  71         reg = __raw_readl(regs + S3C64XX_UINTM);
  72         reg &= ~(1 << bit);
  73         __raw_writel(reg, regs + S3C64XX_UINTM);
  74 }
  75
  76 static void s3c_irq_uart_ack(unsigned int irq)
  77 {
  78         void __iomem *regs = s3c_irq_uart_base(irq);
  79         unsigned int bit = s3c_irq_uart_bit(irq);
  80
  81         __raw_writel(1 << bit, regs + S3C64XX_UINTP);
  82 }
  83
  84 static void s3c_irq_demux_uart(unsigned int irq, struct irq_desc *desc)
  85 {
  86         struct s3c_uart_irq *uirq = desc->handler_data;
  87         u32 pend = __raw_readl(uirq->regs + S3C64XX_UINTP);
  88         int base = uirq->base_irq;
  89
  90         if (pend & (1 << 0))
  91                 generic_handle_irq(base);
  92         if (pend & (1 << 1))
  93                 generic_handle_irq(base + 1);
  94         if (pend & (1 << 2))
  95                 generic_handle_irq(base + 2);
  96         if (pend & (1 << 3))
  97                 generic_handle_irq(base + 3);
  98 }
  99
 100 static struct irq_chip s3c_irq_uart = {
 101         .name           = "s3c-uart",
 102         .mask           = s3c_irq_uart_mask,
 103         .unmask         = s3c_irq_uart_unmask,
 104         .mask_ack       = s3c_irq_uart_maskack,
 105         .ack            = s3c_irq_uart_ack,
 106 };
 107
 108 static void __init s3c_init_uart_irq(struct s3c_uart_irq *uirq)
 109 {
 110         struct irq_desc *desc = irq_to_desc(uirq->parent_irq);
 111         void __iomem *reg_base = uirq->regs;
 112         unsigned int irq;
 113         int offs;
 114
 115         /* mask all interrupts at the start. */
 116         __raw_writel(0xf, reg_base + S3C64XX_UINTM);
 117
 118         for (offs = 0; offs < 3; offs++) {
 119                 irq = uirq->base_irq + offs;
 120
 121                 set_irq_chip(irq, &s3c_irq_uart);
 122                 set_irq_chip_data(irq, uirq);
 123                 set_irq_handler(irq, handle_level_irq);
 124                 set_irq_flags(irq, IRQF_VALID);
 125         }
 126
 127         desc->handler_data = uirq;
 128         set_irq_chained_handler(uirq->parent_irq, s3c_irq_demux_uart);
 129 }
 130
 131 /**
 132  * s3c_init_uart_irqs() - initialise UART IRQs and the necessary demuxing
 133  * @irq: The interrupt data for registering
 134  * @nr_irqs: The number of interrupt descriptions in @irq.
 135  *
 136  * Register the UART interrupts specified by @irq including the demuxing
 137  * routines. This supports the S3C6400 and newer style of devices.
 138  */
 139 void __init s3c_init_uart_irqs(struct s3c_uart_irq *irq, unsigned int nr_irqs)
 140 {
 141         for (; nr_irqs > 0; nr_irqs--, irq++)
 142                 s3c_init_uart_irq(irq);
 143 }